Ti-Cu-Zr-Fe-Nb ultrafine structure-dendrite composites with good mechanical properties and biocompatibility

Ti-Cu-Zr-Fe-Nb ultrafine structure-dendrite composites were designed by inducing Nb and more Ti to a Ti-Cu-Zr-Fe glass-forming alloy composition and prepared by copper mold casting. The composite alloys consist of β-Ti dendrites and ultrafine-structured CuTi2 and CuTi phases as well as a trace amount of glassy phase. The volume fraction of β-Ti dendrites increases with the increase in content of Nb which acted as the β-Ti phase stabilizer in the alloys. The composites exhibit high compressive yield strength exceeding 1200 MPa, maximum strength around 1800 MPa and low Young's modulus around 48 GPa. The plasticity of the alloys is strongly influenced by the volume fraction and morphology of the dendritic β-Ti phase, and the compressive plastic strain was enlarged from 5.9% for the 4 at% Nb alloy to 9.2% for the 8 at% Nb alloy. The preliminary cell culture experiment indicated good biocompatibility of the composite alloys free from highly toxic elements Ni and Be. These Ti-based composite alloys are promising to have potential structural and biomedical applications due to the combination of good mechanical properties and biocompatibility.